Frilly, on the front bump out, the stone (man made, 2" thick) with a cap, for water run off, is a great idea! Typically siding trim is not run along the top of stone, but it's your choice.
Stone, or no stone, IMPO emphasizing only the gable with shakes seems more attractive.
Question: Is the gable vent staying? If so, It might be a good idea to paint it to blend in with the final color of the shakes as best you can to yield attention to the gingerbread. If the vent is gone, or will be gone, never mind.
As for the arbor idea, a flat arbor seems to not emphasize your beautiful door any more than it is without an arbor. I have two suggestions for the front door area. 1) For unification, build a small false gable, centered over the door to match the large one, and finish it the same, with shakes and the gingerbread, or, 2) If your heart is set on an arbor, build one in a gable style, centered over the door, and there are many possibilities on finishing or styling the gable end of an arbor.
